The United States said on Monday it had pulled its ambassador out of Damascus because of threats to his safety in Syria, where protesters are trying to end 41 years of authoritarian rule by the Assad family.

Ambassador Robert Ford had angered the Syrian government by cultivating contacts with the 7-month-old grass-roots movement against Syrian President Bashar al-Assad, leading to attacks on his embassy and residence, diplomats said.

The Western diplomats told Reuters Ford left Syria over the weekend following a series of incidents that caused physical damage to U.S. property but no casualties.

“Ambassador Robert Ford was brought back to Washington as a result of credible threats against his personal safety in Syria,” said U.S. State Department spokesman Mark Toner.